Molding compositions based on ethylene-vinyl acetate copolymers and pitch

ABSTRACT

Molding compositions based on ethylene-vinyl acetate copolymers and pitch comprising a content of A. from 20 percent to 70 percent by weight of a coal tar pitch having a softening point of from 80* to 200*C (DIN 1995) B. from 10 to 75 percent by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of from 30 to 80 percent by weight of the copolymer, and C. from 5 to 50 percent by weight of a thermoplastically shapable polymer having a freezing temperature of below -30*C.

United States Patent 1191 Reinecke et al. Nov. 5, 1974 [54] MOLDING COMPOSITIONS BASED ON 3,349,051 1967 Alexander 260/285 AS ETHYLENEVINYL ACETATE 3.635.863 1/1972 Drukker 260/285 As COPOLYMERS AND F FOREIGN PATENTS OR APPLICATIONS [75] Inventors: Herbert Remecke; Klaus Adler? 602,582 5/1948 ore-I11 Britain 260/285 AS Johann Bauer, all of Burghausen; Reinhard Kretschmer, Munich; a Gel-hard L h f o Primary ExaminerAllan Lieberman Engelbert Pichler, Burghausen, all Assistant Exammer s- FOX I f Germany Attorney, Agent, or FirmHammond & LIttell [73] Assignee: Wacker-Chemie, GmbI-I, Munich,

[57] ABSTRACT [22] Filed: Sept 1972 Molding compositions based on ethylene-vinyl acetate [21] Appl. NO; 286,963 copolymers and pitch comprising a content of A. from percent to 70 percent by weight of a coal F A P D t tar pitch having a softening point of from 80 to 200C oreIgn pp Ica Ion rlorl y a a 1995) Sept. 27, 197] Germany 2148186 B. from 10 to 75 percent by weight of an 52 us. (:1 260/285 AS, 260/285 AV, ethylene-vinyl acetate COPOIYmeY having vinyl 260/285 R, 260/285 A, 260/285 B, etate content of from 30 to 80 percent by weight of H 260/3122 the copolymer, and [51] Int. Cl. C08f /52 0 from 5 {0 percent by weight of a [58] Field of Search 260/285 AV, 28.5 AS thermoplastically shapable polymer having a freezing temperature of below 30C. [56] References Cited UNITED STATES PATENTS 6 Clam, N0 Drawmgs 3,309,329 3/1967 Schultz et al. 260/285 AV MOLDING COMPOSITIONS BASED ON ETI-IYLENE-VINYL ACETATE COPOLYMERS AND PITCH THE PRIOR ART The production of molding compositions having good mechanical properties by mixing pitch with polymers is known. However, not all polymers are suitable; for example, a composition of polyethylene with pitch results in very brittle products, while from ethylenepropylene-diene rubber and pitch a composition is formed which has no strength.

In DAS 1,231,006, molding compositions consisting of 0.1 to 75 percent by weight of pitch and 25 to 99.9 percent by weight of ethylene-vinylacetate copolymer with a vinyl acetate content between 5 and 50 percent weight are described. Such mixtures have good mechanical properties. If, however, molding compositions which withstand higher thermal stresses are needed, pitch of a high softening point must be used. This, however, leads to molding compositions which are very hard. They have a Shore-A hardness of over 90, and foils made therefrom are stiff at normal temperatures. While such foils show a good thermal stability (e.g., when installed in hot bitumen or under solar radiation) which would make them suitable as roofing strip, it is difficult to install them because of their stiffness.

OBJECTS OF THE INVENTION An object of the present invention is the obtaining of a molding composition based on ethylene-vinyl acetate copolymers and pitch which has good mechanical properties, and improved low temperature stability and high thermal stability.

Another object of the present invention is the obtaining of a molding composition based on ethylene-vinyl acetate copolymers and pitch consisting essentially of (A) from 20 to 70 percent by weight of a coal tar pitch having a softening point (DIN 1995) of from 80 to 200C, (B) from 10 to 75 percent by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of from to 80 percent by weight of the copolymer, (C) from 5 to 50 percent by weight of a thermoplastically shapable polymer having a freezing temperature of below 3 0C, (D) from 0 to 10 percent by weight of additives selected from the group consisting of pigments, fillers, stabilizersand processing aids.

These and other objects of the invention will become more apparent as the description thereof proceeds.

DESCRIPTION OF THE INVENTION Molding compositions based on ethylene-vinyl acetate copolymers and pitch have now been found. The molding compositions are characterized by a content ofl A. from 20 to 70 percent by weight, preferably 40m 60 percent by weight of coal tar pitch having a softening point of 80 to 200C, preferably 100 to 195C (DIN 1995),

B. from 10 to 75 percent by weight, preferably 30 m 60 percent by weight of ethylene-vinylacetate copolymer with a vinyl acetate content of 30 to80 percent by weight, preferably 40 to 70 percent by weight of the copolymer,

C. from 5 to percent by weight, preferably 10 to 30 percent by weight of thermoplasticallyshapable polymers, whose freezing temperature is below -30C, and possibly fillers, stabilizers as well as processing aids.

More particularly the invention relates to a molding composition based on ethylenevinyl acetate copolymers and pitch consisting essentially of (A) from 20 to percent by weight of a coal tar pitch having a softening point (DIN 1995) of from 80to 200C, (B) from 10 to percent by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of from 30 to percent by weight of the copolymer, (C) from 5 to 50 percent by weight of a thermoplastically shapable polymer having a freezing temperature of below 30C, (D) from 0 to 10 percent by weight of additives selected from the group consisting of pigments, fillers, stabilizers and processing aids.

In addition to their good tearing strength and tensile strength, the molding compositions of the invention have improved low temperature stability. Their coldbreak temperature is lower than in pitch-polymer mixtures known until now. At the same time the molding compositions of the invention have also a high thermal stability. Further they show an elastic behavior, in contrast to the known molding compositions, which exhibit a plastic stress-strain characteristic.

The molding compositions are especially suitable for the production of insulating 'foils such as roofing strips and foils for construction seals. These insulating foils utilize especially the advantageous properties of the molding compositions. Due to the high thermal stability, the foils are installable in hot bitumen and remain hard enough under solar radiation to walk on. On the other hand, the foils are soft enough also at normal temperature and even at cold outside temperatures to insure easy handling. Moreover, the foils are swelljoinable, resistant to weathering (ozoneand lightstable) and have fungicidal properties.

In addition, the molding compositions can be used for example also as sound-proofing materials, groundwater protection coatings, sealing compounds and for the production of shaped bodies.

The molding compositions are produced by mixing the individual components, together while raising the temperature, for example in a mixing mill, a banbury mixer, an internal or screw mixer. The order in which components are added is of no importance. It is however advantageous to premix the polymer components together and to add jointly the remaining ingredients. The temperature in the mixing operation is usually in the melting range of the thermoplastically shapable polymers (Component C).

Commercial products obtain by distillation from coal tar may be used as coal 'tar pitch (Component A).

The softening temperature of the coal tar pitch, determined according to DIN 1995, should not be below 80C and not above 200C and preferably is between to C. Otherwise, the mechanical values of the mixtures will be impaired.

Component B consists of copolymers of ethylene with vinyl acetate, the content of the vinyl acetate being from 30 to 80percent by weight, preferably from 40 to 70 percent by weight. These polymers are produced by knownprocesses, often by free-radical emulsion polymerizations, e.g., according to German Pat. No. 1,133,130 or US. Pat. No. 3,563,963, for example the VAE type copolymers of Wacker-Chemie GmbH. The quantities used are variable within wide limits.

As thermoplastically shapable polymers, there enter into consideration both elastomers, such as natural rubber, synthetic rubber, for example ethylene-propylene Ethylene-vinyl acetate copolymer of Wacker-Chemie GmbH with 60% vinyl acetate and a melt index i 0.25

rubber, ethylene-propylene-diene rubber, acrylonitrile 2) Dutra| TER 048/5 Ethylene-propylene-butacliene rubber, butadlene-styrene rubber, acrylonitrile- 5 lerpolymer of Momecatini. Mooney viscosity ML-4, 69 butadlenigtyrenedrublpelr, lsopreinfil rubber, chloro 3) 230 Polychlmoprene rubber of Bayer, prene ru er, an et y ene-vlny c orlde rubber, or Mooney viscosity Mk4, 95410 thermoplasts, Such as polyethylene, polyvmyl chlgnde, 4) Perbunan" N 2810 Butadiene-acrylonitrile rubber of plasticized polyvinyl chloride, polyvinyl chloride plastiaggg g i g fg y y sols p y y or g Preferably P l l H 70 F Stabilized Suspension polymerized polyvinyl ylene or so-ealled thermoplastlc rubbers based on chloride of Wac -C e c GmbH. butadiene-styrene or polyurethane are used. The addi- "5 2 j will 2 IDans of tion of- Component C brings about improvements aliz g aj an Hcdd ready n quantltles of 5 percent by weight; usually 6) P1256501 H 70 F Polyvinyl chloride H 70 F of quantities of to 30 percent by weight are used. i i-g??? P 50 paso luyp aatc Stab1llzers, fillers, pigments and processmg alds may 7) uHypalonn crossfinked chlomsulfmmcd be added to the moldlng composltlons of the invention polyethylene of Du Pont, Mooney ln quantities up to 50 percent by weight collectively or viscisity i indi dua 8) Eplkote" 828 Epoxy resin from epichlorohydrin i and diphenylolpropane of Shell Examples of stablllzlers are polycarbodlamldes, 20 (crosslinkecl) vinylnaphthalene, lead compounds and alkylated phe- 9) x i lj" PU Polyurethane plastlclzer of Bayer nols. Examples of fillers are carbon black, chalk, ka- TR 4122 rubbe" polymerlzate from o m, quartz powder, kleselguhr, talc and heavy spar. butadiene-styrene of shell, melt Examples of plgments are the conventional pigments index at 5 g load and C. 22 for plastics such as zinc oxide. Examples of processing '25 g/ 11 D 485 h 1 alds are waxes, factlces, coumarone reslns, plastlclzer esmopan If asnc polyurethane rubber esters, and stearic acid. 12) Hycar" 1072 Acrylonitrile-butadiene rubber of The following examples are illustrative of the inven- 93 .:F: welg acry onl n e, o y welg tlon without bemg llmltatlve in any manner. acrylic and melhacryfic acid 30 Mooney viscosity ML-4, -60 EXAMPLE 1 l3) Low-pressure polyethylene of Wacker-Chemie. GmbI-I, d r 0. 4 Mixtures were prepared from the following compoy 9 7 nents as given in the Table by mixing first the polymer components on a mixing mill at 160C and adding the EXAMPLE 2 remalnlng components to the mlxlng mlll. After sheet- 35 ing out, the properties of the mixtures were ascertained On a drum a homogeneous mixture was produced at and likewise reported in the Table. 150C from coal tar pitch, ethylene-vinyl acetate co- TABLE Mixtures Ingredients 1 2 3 4 5 6 7 8 9 10 l 1 l) VAE 611 1 100 80 80 80 100 80 80 so so Coal Tar Pitch, 100 100 100 100 100 100 100 I00 100 100 Softening Point C 2) Dutral" TER 2) 20 3) Baypren" 230 3) 20 4) Perbunan" N 2810 4) 20 5) H 70 F Stabilized 5) l0 6) Plastisol H 70 F 6) 20 7) Hypalon" 20 7) 20 8) Eplkote 828 8) 5 9) Ultramo1l" PU 9) l0 10) Cariflex" TR 4122 10) 20 2O 11) Desmopan" 485 11) 25 12) Hycar"1072 12) 20 l3) LP-polyethylene, l3) 1O density 0.947 Zinc oxide 3 3 3 3 3 Stearic Acid 0.5 0.5 0.5 0.5 0.5 l l 0.5 1 1 0.5 Tearing Strength 55 35 60 49 45 51 42 46 62 51 40 k /cm Tgaring Elongation 390 360 470 575 270 480 340 430 265 Resistance to continued 25 20 34 26 20 25 21 21 33 29 27 Tearing kp/cm Shore A hardness 23 73 75 80 77 75 84 76 80 96 80 82 60 30 39 47 38 34 56 44 44 59 50 54 80 20 20 20 20 20 28 24 20 43 21 31 Cold Impact Resistance 5 15 10 l0 l0 l0 l0 l5 l0 l0 l5 C (according to Williams, 1C1) In the above Table, the constituents of the tradenamed items and manufacture are as follows:

polymer and polyethylene. For comparison also a mixture without polyethylene was prepared.

VAE61l (l) 100 100 Low-pressure polyethylene Density 0.947 20 Coal tar pitch, Softening Point 160C 100 I00 Shore A hardness It can be noted that the Shore-A hardness of the mixture with polyethylene are substantially better at all temperatures.

Also the cold stability was good. A foil 1 mm thick of the above-described composition with polyethylene could be bent at around a mandrel of mm diameter within 3 sec without cold-break occurring.

As a further advantage it is found that due to Component C the heat shrinkage decreases. A foil which consisted only of VAE and pitch and was prepared on a test calender had a shrinkage of 6 percent at 80C. After addition of 20 percent by weight of polyethylene the shrinkage dropped to 0.5 percent at 80C under the same calender conditions.

The preceeding specific embodiments are illustrative of the practice of the invention. It is to be understood however that other expedients known to those skilled in the art or disclosed herein may be employed without departing from the spirit of the invention or the scope of the appended claims.

We claim:

l. A molding composition for the preparation of foils based on ethylene-vinyl acetate copolymers and pitch consisting essentially of (A) from 40 to 60 percent by weight of a coal tar pitch having a softening point (DIN 1995) of from C to C, (B) from 30 to 60 percent by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of from 50 to 70 percent by weight of the copolymer, (C) from 10 to 30 percent by weight of a thermoplastically shapable polymer having a freezing temperature of below -30C, (D) from 0 to 10 percent by weight of additives selected from the group consisting of pigments, fillers, stabilizers and processing aids.

2. The molding composition of claim 1 wherein component C is a thermoplast.

3. The molding composition of claim 2 wherein said thermoplast is polyethylene.

4. The molding composition of claim 1 wherein component C is an elastomer.

5. The molding composition of claim 4 wherein said elastomer is a synthetic thermoplastic rubber.

6. The molding composition of claim 5 wherein said synthetic thermoplastic rubber is selected from the group consisting of styrene-butadiene thermoplastic rubbers and polyurethane thermoplastic rubbers. 

1. A MOLDING COMPOSITION FOR THE PREPARATION OF FOILS BASED ON ETHYLENE-VINYL ACETATE COMPOLYMERS AND PITCH CONSISTING ESSENTALLY OF (A) FROM 40 TO 60 PERCENT BY WEIGHT OF A COAL TAR PITCH HAVING A SOFTENING POINT (DIN 1995) OF FROM 100*C TO 195*C, (B) FROM 30 TO 60 PERCENT BY WEIGHT OF AN ETHYLENEVINYL ACETATE COPOLYMER HAVING A VINYL ACETATE CONTENT OF FROM 50 TO 70 PERCENT BY WEIGHT OF THE COPOLYMER, (C) FROM 10 TO 30 PERCENT BY WEIGHT OF AN THERMOPLASTICALLY SHAPABLE POLYMER HAVING A FREEZING TEMPERATURE OF BELOW -30*C, (D) FROM 0 TO 10 PERCENT BY WEIGHT OF ADDITIVES SELECTED FROM THE GROUP CONSISTING OF PIGMENTS, FILLERS, STABILIZERS AND PROCESSING AIDS.
 2. The molding composition of claim 1 wherein component C is a thermoplast.
 3. The molding composition of claim 2 wherein said thermoplast is polyethylene.
 4. The molding composition of claim 1 wherein component C is an elastomer.
 5. The molding composition of claim 4 wherein said elastomer is a synthetic thermoplastic rubber.
 6. The molding composition of claim 5 wherein said synthetic thermoplastic rubber is selected from the group consisting of styrene-butadiene thermoplastic rubbers and polyurethane thermoplastic rubbers. 